Patent GB-809612-A (GB)
Title: Improvements relating to the filling and closing of bags
IPC: B65B51/07
Filed: 1956-06-18
Abstract: 809,612. Filling and closing bags. ST. REGIS PAPER CO. June 18, 1956 [June 27, 1955], No. 18777/56. Class 94(1). In a bag-filling and closing machine, collapsed gussetted bags 30 are removed in succession from a stack in a magazine 31 by an oscillating sucker 35 which lifts each bag over a retaining finger 36 and then releases it so that it falls between plates 47, 48 until its base is arrested by a stationary guide trough 53. The plates 47, 48 form the side walls of a reciprocable holder 33 which has a rear wall constituting a pusher and is coupled to the rod 52 of a piston 51 operating in an air cylinder 50. The holder is moved to the left by the piston to position the mouth of the bag for engagement by co-operating endless belts 41, 42 which convey it to a filling station where a reciprocable nozzle 43 is caused to descend into the bag, thus spreading the belts apart so that they hold the lips of the bag tightly about the nozzle, and a weighed charge of material is fed into the bag through the nozzle. The lower end of the bag is supported during the filling operation by a chair 40 which is jigged by an eccentric 80 driven by a motor 79. The nozzle 43 is then withdrawn and the belts 41, 42 convey the filled bag 39 to mechanism 45 which sews a closure tape to the bag mouth, the base of the bag being supported by a delivery conveyer 46. The movement of the bag 39 from the filling to the closing station is assisted by a collapsible pusher 66, attached to an extension of the plate 47, which engages the rear edge of the bag when the holder makes its next feeding stroke and is collapsed by a cam-operated linkage during the return stroke of the holder so as to clear the next empty bag. The piston rod 52 is coupled to a rack 59 meshing with a pinion 60 which drives the end pulleys 41a, 42a of the belts 41, 42 through gearing comprising a ratchet 61 and pawl 62 so that the belts are driven intermittently in one direction only. Pressure air is supplied alternately to the opposite ends of the cylinder 50 through pipes 57, 58 under the control of a valve 54, timer 55 and microswitches 64, 72 actuated by a cam element 65 on the piston rod 52, the timer being arranged to delay the movement of the piston 51 to the left after the microswitch 65 has been actuated until an empty bag 37 has been delivered to the holder 33 and a charge of material has been fed into a bag 39 at the filling station. The mechanism 34 operating the sucker 35 is controlled by a microswitch 63 actuated by the end of the piston rod 52. The nozzle 43 is raised and lowered by an air cylinder 67 controlled by a valve 68 and microswitches 69 and 71 actuated respectively by a cam element 70 on the rod 52 and the cam element 65. In a modification, Figs. 7-9 (not shown), the nozzle is raised and lowered through linkage actuated by a cam carried by the holder 33. The nozzle comprises pivoted tapered flaps which are normally closed to prevent discharge of material and to allow easy entry of the nozzle into a bag, but are opened after the nozzle has entered the bag by the engagement of levers thereon with fixed abutments. The discharge of material from a weighing device 46a is effected by the opening of gates 74, 75 which are operated by mechanism 76 controlled by a microswitch 77 actuated by a finger 78 on the nozzle 43. The belts 41, 42 pass over the drive pulleys 41a, 42a, fixed pulleys 41c, 42c and 41d, 42d arranged adjacent the leading and trailing edges of a bag at the filling station, and movable tensioning pulleys 41b, 42b acted on by springs 91, 92. The tension in the belts may be increased when the nozzle is in the raised position by a cam-operated linkage which moves the pulleys 41b, 42b further to the right. The mouth of each bag is opened for the reception of the nozzle 43 by a resiliently-mounted knife 44 which cuts through the median fold of the gusset at the leading edge of the bag. The holder 33 is adjustable to suit bags of different sizes.